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How a heat pump works

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Re: How a heat pump works

#81

Post by sbradford26 »

helen___keller wrote: post #30
boringg wrote: post #7

What is going on? Is there a global push to get everyone to switch to heat pumps. It seems that there is heat pump content everywhere. Clearly there is a push. I understand that its for climate benefits but it feels very coordinated. edit: didn't realize the attention I would get. Let me add someone answered my question -- a good product market fit and people talking is probably where the push came from. That said HV…

I’ve been independently interested in heat pumps because I need to replace my old end-of-life system and I’ve been interested if a modern cold-weather mini split system is a better investment. There’s lots of conflicting info I’ve found on if heat pumps perform in freezing weather and at what kind of efficiency. I’m sure there’s others in my position.

So largely I think the confusion stems from there being two major different "types" of heat pumps and they perform very differently.

The first is your conventional type system, this is usually what AC units are in the US. They run at maybe 1 or 2 speeds. These type of heat pumps are common in the southern parts of the US but also will be found paired with a gas furnace in the northern US. Since they don't adjust their output dynamically they tend to start losing capacity/efficiency significantly around 25-30F.

The second is an inverter driven heat pump. You usually find these in mini splits but they can also be found in a standard air handler form factor that would replace a furnace. The inverter allows the compressor to adjust based on demand and exterior temperature to maximize efficiency. This allow these units to operate efficiently down to -13F depending on the unit. Now there will still be some capacity loss at those temps so during the design of the system this has to be taken into account.

For detailed information on the efficiency of heat pumps I would check out NEEPs website. It is a great resource, it will show you capacity and efficiency (COP) of tons of different units across their operating temperatures.

https://ashp.neep.org/

Re: How a heat pump works

#82

Post by zeroonetwothree »

nicoburns wrote: post #55
nashashmi wrote: post #16

Earlier quoted context omitted.

They are not more energy efficient than burning gas. Edit: since i am getting downvoted to oblivion, let me fight back here. I genuinely wished heat pumps would be more efficient and in theory they can be. I would love to not generate heat and just use the outside heat energy and compress it down into a smaller location. But compressing and decompressing is not an energy efficient task. It takes a lot of work. Mechan…

Well of course when talking about efficiency you have to specify what you are being efficient with respect to: what's most energy efficient might be different to what's most cost efficient which might be different to what's most carbon efficient. Cost is going to vary greatly on the electricity and gas prices in your area, so it's hard to give a definitive answer there. With regards to energy efficiency, my understan…

There is also up to 10% loss from transmission/distribution. So that makes the two closer though heat pumps still win.

Re: How a heat pump works

#83

Post by JTbane »

mhb wrote: post #8
boringg wrote: post #7

What is going on? Is there a global push to get everyone to switch to heat pumps. It seems that there is heat pump content everywhere. Clearly there is a push. I understand that its for climate benefits but it feels very coordinated. edit: didn't realize the attention I would get. Let me add someone answered my question -- a good product market fit and people talking is probably where the push came from. That said HV…

That and gas stoves bad.

Gas stoves bad, yes. If you do a modicum of research you can see that they cause indoor air pollution (and most people don't have real hood vents to outside the building).

Re: How a heat pump works

#84

Post by masklinn »

hexmiles wrote: post #21
boringg wrote: post #7

What is going on? Is there a global push to get everyone to switch to heat pumps. It seems that there is heat pump content everywhere. Clearly there is a push. I understand that its for climate benefits but it feels very coordinated. edit: didn't realize the attention I would get. Let me add someone answered my question -- a good product market fit and people talking is probably where the push came from. That said HV…

I don't know if it applies everywhere, but two factor come to mind: the (somewhat recent) change in energy and gas price did make heat pump a lot more competitive with more traditional heating solutions, and recently there are a lot of economic incentives (at least, here in Europe) to renovate house for energy efficiency, which make solar panel and heat pump very attractive.

> and recently there are a lot of economic incentives (at least, here in Europe) to renovate house for energy efficiency, which make solar panel and heat pump very attractive.

Economic but also legal and geopolitical: fuel oil furnaces are getting restricted or banned, and the combination of climate change, air quality standards, and russian instability makes gas look at lot worse than it did 10 or 20 years back.

Re: How a heat pump works

#85

Post by oceanplexian »

wongarsu wrote: post #27
boringg wrote: post #7

What is going on? Is there a global push to get everyone to switch to heat pumps. It seems that there is heat pump content everywhere. Clearly there is a push. I understand that its for climate benefits but it feels very coordinated. edit: didn't realize the attention I would get. Let me add someone answered my question -- a good product market fit and people talking is probably where the push came from. That said HV…

For a long time the main problem of heat pumps was that while they are more efficient, a kilowatthour of gas or oil is much cheaper than a kilowatthour of electricity. But in the last two years natural gas prizes have gone crazy, removing that price disadvantage. Of course heat pumps emitting no particulates and being able to run on renewables are also good reasons, especially as the health impact of living in cities…

An overlooked benefit is that they actually improve comfort over a boiler in a dry climate, so if you live somewhere with low humidity they help keep the air less dry. They also give you heating and cooling.. for places that don’t have Air Conditioning it’s a worthwhile upgrade.

Re: How a heat pump works

#86

Post by zeroonetwothree »

asow92 wrote: post #73
prottog wrote: post #57

Earlier quoted context omitted.

In the Northeast with that much square footage, you would be better off with ground-source heat pumps (whether open or closed loop), rather than the normal air-source heat pumps.

I guess the concern I have with all this is that my current system works well, and I don't want to spend $10K+ unless it brings down my heating costs significantly. Could a ground-source heat pump system do that?

It depends on relative prices in your area so we can’t answer that. You would have to calculate it yourself.

Typically it makes the most sense to do when you need to replace your system.

Re: How a heat pump works

#87

Post by scythe »

boringg wrote: post #7

What is going on? Is there a global push to get everyone to switch to heat pumps. It seems that there is heat pump content everywhere. Clearly there is a push. I understand that its for climate benefits but it feels very coordinated. edit: didn't realize the attention I would get. Let me add someone answered my question -- a good product market fit and people talking is probably where the push came from. That said HV…

I'm just annoyed that I was talking about heat pumps for the last five years or so and nobody is giving me any credit for running an international conspiracy.

But seriously, it's just the next fish to fry after electric vehicles became a solved problem. Heating buildings is somewhere around 10-25% of total emissions and probably the largest remaining single factor not directly addressed by switching the electric grid to renewables, so many people concerned about climate change have converged on it.

Re: How a heat pump works

#88

Post by kzrdude »

suoduandao2 wrote: post #24
kzrdude wrote: post #10

Earlier quoted context omitted.

Who do you imagine is pushing, and why? Don't you want to resist to turn to explanations like this, that require some invisible force to pull the strings? I think there are more realistic ways to imagine this happening. If for example a pop star is getting a lot of attention, in multiple countries, what is the mechanism behind that? And is it orchestrated?

Explanations like what? Op didn’t put forward much in the way of hypotheses. If you have a good explanation of the mechanism by which attention accumulates around topics that doesn’t require orchestration it would be interesting to hear, it seems like a poorly understood phenomenon.

The way I read it, Op was suggesting a flirt with conspiratorial thinking ("someone is doing this") and I wanted to turn to something more rational.

I don't really know how trends and fashions form and haven't thought so much about it. Some aspect of it might look like research into the ising model and phase transitions - small changes in "temperature" everywhere in the mass of people might look like a phase transition in the overall mood.

Re: How a heat pump works

#89

Post by masklinn »

jcstauffer wrote: post #5
WatchdogReset wrote: post #2

The heat pumps are one of the means of heating (and air conditioning) in the heart of the news. What is their principle of operation. You can ask questions here if there are points to clarify in the course

I'd like to get a heat pump to replace my existing baseboard hot-water system (currently powered by an oil furnace) without converting to a heated air system. From what I've read, that's not quite feasible yet, since current systems can't produce a high enough temperature. What are the prospects of that technology becoming viable in the next few years?

> From what I've read, that's not quite feasible yet, since current systems can't produce a high enough temperature.

Is it because baseboard hot-water systems have limited exchange surface surface and thus need very high temperatures to do anything?

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